Aim: To study the effects of 17beta-estradiol on Kv2.1 potassium channel current and delayed rectifier potassium current (IK) in cultured rat hippocampal neurons.
Methods: The effects of 17beta-estradiol on Kv2.1 channel current and IK in cultured rat hippocampal neurons were observed using the whole cell patch clamp techniques.
Results: 17beta-Estradiol was shown to reduce the amplitude of Kv2.1 current and IK in concentration-dependent manners. The IC50s of 17beta-estradiol blocking Kv2.1 and IK were 2.4 and 4.0 micromol x L(-1), respectively. 17beta-Estradiol (3 micromol x l(-1)) significantly shifted the steady-state activation and inactivation curves of Kv2.1 current to negative potentials. However, it only produced the shift of the steady-state activation curve of IK to the negative potential without effect on the steady-state inactivation of IK.
Conclusion: 17beta-Estradiol inhibits Kv2.1 and IK of hippocampus at similar level. The inhibition of 17beta-estradiol on IK current may be partially via blocking Kv2.1 current.